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   How to use a protractor and depth gauge

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How to measure depths using a protractor and depth gauge

Protractor with depth gauge being used to measure the depth of an object

Step 1 – Put protractor in place

Place the protractor on top of the groove/channel.

The locking nut; protractor and depth gauge, rule, ruler

Step 2 – Undo locking nut

Release the locking nut’s grip on the rule by loosening it.

A protractor and depth gauge in use, showing the rule positioned at the bottom of the "hole" being measured

Step 3 – Allow rule to drop into groove/channel

Allow the rule to fall freely to the bottom and use the locking nut to make sure it won’t move.

Part of the rule/blade; protractor and depth gauge, Starrett

Step 4 – Read depth

The measurement can then be read from the rule where it first meets the protractor.

Wonkee Donkee says "To measure a perfectly vertical groove, the ruler must be at a 90 degree angle to the protractor."

How to measure an angle using a protractor and depth gauge

Lining an object against the bottom of the protractor; protractor and depth gauge, rule, ruler, blade

Step 1 – Place object against protractor

Place the object against the bottom of the protractor.

The rule needs to line up with the other side of the angle; protractor and depth gauge, rule, ruler, blade

Step 2 – Line up rule

Line the rule against the other side of the angle.

The locking nut; protractor and depth gauge, rule, ruler, blade, Starrett

Step 3 – Tighten locking nut

Use the locking nut to keep the rule still.

The angle can be taken from the protractor; protractor and depth gauge, rule, ruler, blade

Step 4 – Read angle

The size of the angle can be taken from the protractor.